The asking rent for the two-year renewal was in the mid-$60s per square foot, a source with knowledge of the deal said. The tenant has occupied the entire 28th and 29th floors for over 15 years.

Around since 1926, Phillips Nizer is a full-service domestic and international law firm.

Kushner, run by Chief Executive Officer Jared Kushner, the publisher of CO, bought the 41-story, 1.5-million-square-foot 666 Fifth Avenue between West 52nd and West 53rd Streets, for $1.8 billion in 2007. It was the largest single building transaction at the time. Kushner brought Vornado in as a partner in the building’s office portion in 2011 and a year later, Vornado acquired the building’s 114,000-square-foot retail condominium from Kushner for $707 million.

Jared Solomon of Vornado represented the landlords in the deal and JLL’s Alexander Chudnoff, Paul Glickman and Scott Vinett represented Phillips Nizer. Mr. Solomon didn’t respond to a request for comment and nor did the JLL brokers via a spokesman.

Other office tenants in the building include asset manager Millennium Management and law firms Vinson & Elkins and Akerman LLP. Retailers include Uniqlo, which broke a city record in 2010 with its $300 million 15-year lease, and Hollister.